MAVEN probe finds Mars is losing its atmosphere to space

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NASA’s MAVEN spacecraft only reached Mars back in September, but already it is turning up some intriguing information about how the Red Planet is evolving. MAVEN (which stands for Mars Atmosphere and Volatile Evolution) has reported that Mars is in danger of losing what little atmosphere it has to the cold depths of space. And all this before it has even reached its optimal orbit.

MAVEN was launched in November of 2013 to help us answer some of the broader questions about Mars–the sort of thing a rover like Curiosity isn’t equipped to answer. Specifically, what’s going on with the Martian atmosphere? Mars sits toward the outside of the “Goldilocks Zone” in our solar system where liquid water can exist. There are times Mars can reach a toasty 70 degrees Fahrenheit at the equator, though it’s usually much colder. The problem is that Mars has an atmosphere 100 times thinner than Earth’s. so it can’t retain much heat.

As the MAVEN probe passed over the Martian upper atmosphere recently, it took measurements of hydrogen, oxygen, and carbon atoms. The oxygen and hydrogen come from the breakdown of water molecules further down near the surface. There is precious little water on mars that isn’t locked up in the ice caps or in the soil, so the high levels of hydrogen in the upper atmosphere were particularly alarming. The massive cloud of hydrogen hovering at the top of Mars’ atmosphere indicates Mars is losing what little atmosphere it has.

Because hydrogen is the lightest element, it floats to the top of any planet’s atmosphere. When it’s up there, it can easily be stripped away by the solar wind. The escape rate of hydrogen indicates Mars could be an even colder and less hospitable place in the future. This also raises concerns about any future efforts to colonize Mars. We don’t exactly have the technology to terraform a planet yet, but what if it can’t even hold an atmosphere?

MAVEN will spend another two weeks gathering preliminary data on Mars as it settles into its orbit and NASA test all the instruments. The initial one-year mission will include several passes through the Martian atmosphere just 77 miles (150km) from the surface. Scientists also plan to use MAVEN to observe the close flyby of a comet in a few days. If MAVEN works longer than a year, it will continue to do science until it can’t anymore.